While looking at an objtool UACCESS warning, it suddenly occurred to methat it is entirely possible to have an OPTPROBE right in the middle ofan UACCESS region.

In this case we must of course clear FLAGS.AC while running the KPROBE.Luckily the trampoline already saves/restores [ER]FLAGS, so all we needto do is inject a CLAC. Unfortunately we cannot use ALTERNATIVE() in thetrampoline text, so we have to frob that manually.